There's an important, although little-known, advantage to cool roofs: They help cool the planet.

The Summer 2006 heat wave resulted in dramatic increases in both A/C electric bills and homeowners’ interest in cool roofs.As Home Energy readers know, cool roofs can reduce A/C use by up to 20% and improve a home’s comfort in the event of a power loss (see “Cool Colored Roofs,” HE March/April ’06, p. 12). This article focuses on a lesser known cool roof benefit— their contribution to the Earth’s albedo or reflectivity. Approaches such as cool roofs that instantly reduce global warming may well turn out to be a critical tool in countering the risk of abrupt climate change.